Expert systems and algorithms such as rule-based forward chaining which serve them are known.
DFS (depth first search) computerized algorithms for searching, e.g. data stored as a topological tree in computer memory, are known.
Dijkstra's algorithm is one of various known graph search algorithm variations that solve the single-source shortest path problem for a graph with nonnegative edge path costs, producing a shortest path tree.
Using known spectral graph analysis techniques, topological properties (e.g., patterns of connectivity) of graphs can be analyzed in terms of spectral graph theory which, according to Wikipedia, “is the study of properties of a graph in relationship to the characteristic polynomial, eigenvalues, and eigenvectors of matrices associated to the graph, such as its adjacency matrix or Laplacian matrix. For example, an undirected graph has a symmetric adjacency matrix and therefore has real eigenvalues (the multiset of which is called the graph's spectrum) and a complete set of orthonormal eigenvectors. While the adjacency matrix depends on the vertex labeling, its spectrum is graph invariant. Spectral graph theory is also concerned with graph parameters that are defined via multiplicities of eigenvalues of matrices associated to the graph, such as the Colin de Verdière number.”
US Patent Application 20120016678, assigned to Apple, is entitled Intelligent Automated Assistant, published Jan. 19, 2012, and filed Jan. 10, 2011. This published application describes an intelligent automated assistant system which “engages with the user in an integrated, conversational manner using natural language dialog, and invokes external services when appropriate to obtain information or perform various actions. The system may be implemented using any of a number of different platforms, such as the web, email, smartphone, and the like, or any combination thereof. In one embodiment, the system is based on sets of interrelated domains and tasks, and employs additional functionally powered by external services with which the system can interact.”
The disclosures of all publications and patent documents mentioned in the specification and of the publications and patent documents cited therein directly or indirectly are hereby incorporated by reference. Materiality of such publications and patent documents to patentability is not conceded.